Speed regulator for engines



Aug. 31, 1943. E. A. HOBART 2,328,452

SPEED REGULATOR FOR ENGINES Filed Aug 50, 1941 s Sheets-Sheet 1 MANIFOLDVAC (INCHES OF MERCU 1 KVA GENERATOR LOAD FREQUENCY 1 KVA GENERATOR LOADTERMINAL VOLTS R; O O

.1 KVA GENERATOR LOAD Jmm pr EDWARD A. HoaaRT. QKMQWW $3M Gummy E.A.'HOBART SPEED REGULATOR FOR ENGINES Aug. 31, 1943.

, 1941 5 Sheets-Sheet 2 Filed Aug. 30

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1943- E. A. HOBART 2,328,452

SPEED REGULATOR FOR ENGINES Filed Aug. 30, 1941 3 Shets-Sheet 3 JmenvpuEDWARD fl-H BART,

Swath/M 5% Patented Aug. 31, 1943 SPEED REGULATOR FOR ENGINES .Edward A.Hobart, Troy, Ohio, assignor to The Hobart Bros. Company, Troy, Ohio, acorporation of Ohio Application August 30, 1941, Serial No. 409,031

1 Claim.

The present invention relates to combined automotive engine sets of theportable type, and more particularly to those units designed forvariable loads such as when the load is suddenly applied and thenwithdrawn.

In the arts there is a necessity for a portable engine especially for analternator outfit in which the frequency of the generated Voltage ismaintained within close limits even when the load on the alternator orany load on the engine is suddenly applied and then withdrawn. Certainkinds of alternating current apparatus as for example can be operatedsatisfactorily only when the frequency of the current is maintainedstrictly constant. This constancy of frequency requires an absoluteuniformity of engine speed. However, in case the engine is of limitedpower and the load is greatly increased, the speed of the enerator wouldordinarily be reduced, and thus thef requency of the generated voltagewould dopart from the required frequency.

The primary object of the present invention is to provide an improvedautomotive engine unit which gives easy constant speed, notwithstandingthe amount of load imposed on the engine, or the abruptness with whichthe load is applied or withdrawn.

As a corollary tothe foregoing object, when the engine is connected toan electric generator, for instance the constancy of frequency requiresuniformity of the instantaneous speed of the unit as a whole, which inturn improves the voltage regulation under load. This object is carriedout, in brief, by, controlling the normal setting of a fly ball governorwith which the engine is usually equipped. Governors of this characteroperate on the centrifugal effect exercised by a pair of fly balls whichmove outwardly as the speed of the engine is increased, and this outwardmovement of the balls is taken through suitablemechanism to a butterflyor other fuel control valve positioned at the carburetor. It has beenfound that notwithstanding the use of a fly ball governor forcontrolling the speed of the engine under load, variations in speed arebound to occur, and these variations manifest themselves by considerableproportional changes in frequency at the generator. Even the slightestchangegin this frequency, brought about by a relatively small change inthe speed of the generator engine unit, may prevent the satisfactoryoperation of certain electrically-driven or controlled devices. A flyball governor, even of the most effective type, serves merely tomaintain a constant average speed of the engine, but

the instantaneous speeds may vary considerably and in turn causecorresponding instantaneous changes of the frequency.

Accordingly, another object of the invention is to provide improvedapparatus by which the operation of an ordinary speed governor may bemodified to maintain a strictly constant instantaneous speed at theengine, regardless of fluctuations in the load applied either at theengine or by any load thereon.

Other objects and features will be apparent upon perusal of thefollowing specification in connection with the accompanying drawings.

In the drawings:

Figure 1 is a diagrammatic layout of a combined engine-generator unitimproved in accordance with the present invention.

Figure 2 is a graph showing the relation between the manifold intakevacuum and the gen orator load.

Figure 3 is also a graph, indicating the improvement in the constancy offrequency brought about by the improved structure.

Figure 4 shows the improvement in voltage regulation which accompaniesthe improvement in the frequency of the generator or speed thereof.

Figure 5 is an enlarged detail view of the improved structure.

Figure 6 shows a modified form of the apparatus.

Figure 7 is a fragmentary view, partly in elevation and partly insection, to expose the interior elements of a typical fly ball governorwhich may be employed in connection with the improved speed regulator.

Figure 8 shows in diagram, with portions in section, still another formof the improved apparatus.

Figure 9 depicts a different form of mechanical connection between thebellows and the fly ball governor than that shown in the other figures.

Figure 10 is a fragmentary sectional view taken along the line Iill 0 inFigure 8.

Referring more particularly to Figure 1., reference numeral l designatesa typical form of internal combustion engine illustrated as that of afour-cylinder type, as indicated by the spark plugs 2. The carburetor ofthe engine is indicated at 3, this carburetor being in communicationwith an intake manifold 4. A flywheel for the engine is indicated at 5,the latter being carried on the main shaft 6. In addition to theflywheel for assisting in maintaining a constant speed at the shaft 6,the engine is provided with a governor, indicated at l, which may be ofthe usual fly ball type and is illustrated in Figure 7. A description ofthe governor will be given when the improvement brought about by thepresent invention is described in detail.

Directly mounted on the shaft 6 or coupled thereto in any suitablemanner when applied for example for operating an alternating generator,there is an exciter, also a main generator generally indicated at 8 and9, respectively. The exciter field is indicated at It and is connectedin shunt to the armature, a resistor I I being connected in series withthe exciter field in order to vary the field current. The main generatorfield is indicated at 12, and it will be noted that the generator fieldis energized with direct current from the armature of the exciter 8. Thmain generator 8 is illustrated as an alternator of the three-phasetype, with the windings l3 positioned at 120 with respect to oneanother.

Assuming that the engine I is of limited power and that a fairly heavyelectrical load is imposed on the generator 9, there is a tendency forthe engine to slow down, at least temporarily, notwithstanding the useof the fly ball governor l which controls the admission of fuel gas tothe engine through the butterfly valve M. This niomentary decrease inspeed not only tends to give the alternator poor voltage regulation, butin addition materially reduces the frequency of the generated voltage.Certain types of electrical apparatus demand constant frequency, usually60 cycles for proper operation, particularly when the element of timesynchronization is involved. Still other apparatus requires that thevoltage applied thereto shall be strictly constant regardless of ieamount of current which is drawn from the generator. The invention asapplied to typical system such as has been described, is illustrated inone of its forms in Figure 5.

In accordance with the invention, certain adjustinents are automaticallymade at the fly ball governor I, and dependent on the intake vacuum ofthe engine to give the governor a new setting at the butterfly or otherfuel intake valve in order to provide more fuel at this point inresponse to an increase in load at the generator. The I rnism forintroducing the new governor ng may take the form of a bellows ordiaphragn wh h translates the changes in the intak vacuum intomechanical movement. The invention is based on my discovery that the infrequency at the generator when U. ad for purpose and therefore thevariations in the speed of the unit follow very closely the changes inthe intake vacuum of the engine, so that the latter may be employed asan initiating force to give compensatory effects, from the speedstandpoint.

A conduit 95 is taken from the intake manifold of the engine, and passesthrough a shut-off valve t.-.s conduit being in communication withinterior of a casing ll, closed at the top and bottom. Within the casingthere is a Sylphon bellows Hi closed at the top by a plate 58 but openat the bottom to receive a reentrant hollow cylindrical member- 2B. Thelatter is provided with an integral plate 2| at the top, this platebeing apertured to receive a rod 22 which is secured to the plate l9, asindicated at The rod 22 is threaded, as indicated at M, rec a flangednut 25. There is a tension 26 positioned between th nut 25 and the plate2!, and contained within the cylindrical member The purpose of thisspring is resiliently to hold the plate I3 at the top of the bellows apredetermined distance from the bottom of the casing H. The rodterminates at the bottom end beyond the nut in an enlarged cylindricalmember 21 which is threaded on the rod 22 by a nut 28.

There is a strap member 25 secured to and extending downwardly from thecasing ll, this strap member being provided with an outwardly extendingstub shaft 36. An inner ball race 3| is keyed to the shaft, andsurrounding the ball race there is a circular disc 32 formingthe otherball race and containing ball bearings by which the disc may be readilyrotated about the shaft 30. The disc 52 has an integral extensionprojecting to th right therefrom, this extension being secured to thecylinder 2? in such a manner that as the cylinder is moved upwardly ordownwardly, the disc 32 is caused rotatably to rock. The disc 22 is alsoprovided with a downwardly extending portion which terminates in a leg33,

adapted to swing between a pair of stops 34, 35,

respectively. The stop 3! may be designated the full load stop and thestop 35 the no load stop, and the :purpose of these stops will beexplained hereinafter.

The lower end of the strap 28 is provided with a journal for a rotaryshaft 36 which is coupled to the main shaft of the engine in anysuitable and Well known manner (not shown). This shaft extends throughthe end of the speed governor 1, which is mounted on the machine in anysuitable manner. The shaft is provided witha reduced diameter portion31, within the governor, and on this shaft portion there is mounted apair of straps 38, the ends of which carry a pair of fly ball Weights 39which terminate at the lefthand end (Figure '7), in a curvilinear or camportion 48. The cam portions are adapted to bear against a grooved wheel4| secured to the shaft portion 31. The groove receives a rollerindicated at 42 which is carried on a lever 43, pivoted at 44. There isan arm secured to the lever 43 and extending upwardly through an openingin the casing 46 of the governor. The pivot point 44 is extended to theexterior of the casing 46 by means of a shaft (not shown), and to thisshaft there is secured a nut 47 which carries the threaded end of a bolt48. The bolt is provided with a rectangular head having an aperture inwhich is inserted one end of a tension spring 49. The other end of thespring is secured to a lever 58 of arcuate shape, pivoted at 5| to thecasing 46, and provided with an upwardly extending apertured arm 52, towhich a nut 53 is secured in any suitable manner. A cap screw 54 isthreaded through the nut 53, this screw being adapted to bear againstthe leg 33 of the disc 32. The arm 45 terminates in a spherical portion55 which is received by a circular opening formed in an enlargedcylindrical end portion 56 of a connecting rod 57. The latter isswivelly connected to a lever 58 which controls a butterfly valve 59,

positioned in an intercommunicating passageway between a carburetor GBand the intake manifold 4 of the engine.

Operation of the mechanical system shown in Figures 1, 5 and 7 phasealternaton as illustrated, the direct current for. its field :beingprovided by the exciter;

Assume still further that the electrical load on the alternator is suchasuto' require absolute-comstancyoffrequency regardless of 7 Whether theload on the generator is highor low orwhether the load is abruptlyapplied or withdrawn. In

case the load is increased, the normal operation: of the governor l, i.e. without the benefit of the present invention', would be to move thebutterfly valve159an'd thereby-increase the amount oi fuel gaspassinginto the. intake man-ifold' lt However,

it has" been" found thatxwhen' the: load has been" increased toa'predeterminedvalue, the govern'or doestnot exercise thesameesensitiveness of con trol at the newiloadsas it did at'the initialloady.

so thattanyrvarlationszin load from the average new load value producefluctuations in the engine speediandtherefore. of the frequencydeveloped at the'main generator.

In accordance with the .presentrinvention, the" setting of thebutterflyor anytruel controlvalve is-changed as the load changes:withoutaffcctingr the sensitiveness of; control :exercised at thegovernor, so that strict uniformity. of speed 'atlthea generator is:assured when .l the load conditionschange. This auxiliary adjustment isbrought about by the use of the bellows I8 :which responds, to theintake vacuum of theengine, the latter. in

turn varying directly with:the.load.imposed on the engine bytheincreased demand. at theigenerator. As the speed of the engine "tends todecrease; the intake vacuumialsodecreases, which in efl'ect causes an'increase inipressureon1topxo-f the plate 23 of thebellows;Thelattertwilliconitract against the pressureaof the atmosphereadmittedto the interiorof the bellowsfthrough the.

vent 6-1, causingtherod .22 to move downwardly and the disc 32*torotateon its.shaftfillrclockwise.. The arms 52; 58-arerockedcounterclockwise, due" to the movementiof the screw54; andithetensioni of the spring 49 is increased, ,causingthearm'45' to moveto'the left. This movement of the arm causes the butterflyvalve 59totakeia; permanent- 1y. new position to. admit; additional fuel to: the

engine in orderto carry the load, butiat thesame time allowingforfurther adjustment from this" new position when the fly ball weightscause .additional movement of: the armAS duei to further variations inthe speed of the engine. Inzone sense the operation of the Sylphonbellows I81 may-be1considered-to give anew setting of'the butterflyvalve-59 asbetween no load andfifullior" half-load,while the speedgovernor. I corrects.- anyminor variationin speed from'the average:speed which isnecessary to carry;the=predeter-- mined load. Thesensitivenessofthe governor is therefore maintained at thenew'loadsetting of the butterfly-valve, resulting in an' absolute com stancyoffrequency produced at-thealternator 9.

The invention is based upon my, discovery that the instantaneous changesin frequency,- due to'a.

variable load, follow almostexactly the instantaneous changes of theintake'manifoldvacuum. This has been expressed graphicallyiniFigures 2and 3. by the curves aand b; respectively.

Curve a shows a variation of frequency, using Gil cycles as anaverage,against. the load as an abscissa, basedion k.v.ai at the generator; Thecurve b is drawn between the manifold vacuum (inches of mercury) and thek.v.a;. generator load as an abscissa; It will be noted that each ofthese two curves has practically the same instantaneous droop.

As a result of the additional control exercised on the butterfly valveby an intake vacuum-responsive device, the frequency: at the generatoris-maintained substantially constant from zerotofullload', as indicatedby the characteristic crin The slight droopin the frequency Figure 3.

around 1%; k. v. a. in the curve 0, and again at: aposition beyond thefull load (4 k. v. a'.) is due to the fact that the engine l. isinherently of the impulse type anddoesnot exert a' strictly continuousrotary eflort at the crankshaft While the invention is intended itprimarily toprovideconstant frequency atthe generator-for archange inload, the fact that the shaft E -isrotated'at a strictly uniformspeedregardlss:

of load also brings'abouta decided improvement '1 This in the voltageregulation at i the generator. isnillustrated in Figure 4, in which thecurve 01 plotted against terminal volts as an ordinate and k. v. a.load'as anabscissa, graphically-depictsthe voltage regulation of thealternator,

using an ordinary speed governor but'without the improved'controlfeature ofthis invention. The" curve e illustrates the improvementbrought about by the use of the Sylphon 18 which respondsto the intakevacuum to give-a new setting to the butterfly valve59 and operating inconjunction" with the speed governor. It willbe noted that the curve 6shows a much flatter regulation than the curve d.

While I have described my improvement in termsof anincrease in load,itwill be understood thatxthe bellows l8 also respondsto an increase inthe intake vacuum when the engine is speeded up, due to reduced loadconditions: Under these circumstances the bellows will expand and inoperating through the described linkage, will give anew setting to thebutterfly valve 59*by which the amount of fuel gas passingfrom thecarburetor to the intake manifold is reduced.

In Figure 6 there is showna modification in' which the Sylphon bellowsis employed to change the length of the connecting rod between the arm45 andthe butterfly valve lever 58", and thus provide adjustment in thismanner; i5 is taken through the valve lfi to a flexible tubing 62" whichcommunicates with the interior of a Sylphon bellows 63.

The Conduit" The endplates G4; 65'

are not rigidly mounted but are adapted to swing.

right or'left' from the position shown in the The ball governor l is.

The end plate 6 is secured, through- The end somewhat similar to thatdescribed in'connectionv with Figure 5' except that the pivotediarms50;, 5| and the cap screw 54 have been eliminated, the spring 4B beingconnected at the right-hand end to a threaded rod l iscrewedin anangeifiprovided on the rim of the governor.

Operation of the structure shown in Figured As the load on thegenerator9 increases, which would. normally cause a reduction in the generatedfrequency, the of the engine ltends tov decrease and its intake vacuumalsotends to:

decrease. Inasmuch as the effect of the vacuum is applied to theinterior of the bellows 63 instead of to the exterior of the bellows, asin the case of Figure 5, the bellows now will expand with the assistingaction of the. spring '59, and in. effect increase the length of theconnecting rod portions H, 72, which, separate the butterfly valve arm58 from the speed governor arm This increase in connecting rod lengthmoves the 58. counterclockwise to open the butterfly valve 59 toadmitlarger quantities of fuel gas to the intake; manifold, thus, in effectto increase the speed of the engine. It will be noted that no change hasbeen made either in the structure or the operation of the fly ballgovernor '2, so that the latter isfrce to exercise its usual speedcontrol function. Thus the butterfly valve is given a new settin inresponse to the change in load at the generator, and the speed governorexercises further control over the butterfly valve in response tochanges in speed of the engine.

The modification shown in Figure 8 employs still different structure forproviding strict uniformity of speed at the generator, regardless of theamount of electrical load or the abruptness with which the load isapplied or withdrawn. In this case the intake vacuum is conductedthrough the conduit l5 and valve it to the interior of a metal tube 75.This tube is closed at its upper end by a closure member il, in which isthreaded a rod '18 which passes through a loeknut 79 mounted on top ofthe closure memher. The lower end of the rod 123 contacts a disc as,against which bears a compression spring 8| contained within the tube76. The latter is secured to the upper face of a bellows 82, which faceis held rigidly in space, as indicated at 83, and may be secured to anyportion of the engine.

The lower end 84 of the bellows is provided with an upstanding tube 35which extends internally of the bellows and recei es the lower end ofthe spring iii. The tubes '25 "and 85 are preferably in. line with oneanother but are not directly socured together. The end 3d of the bellowsis connected through a lever 86., pivoted at t'l' to an arm 88. whichterminates at its lef -hand end in a circular enlargement 88 providedwith an eccentrically located pin 91 The pin 03 is secured to an innerball race fit, the ball bearings being indicated at 52 and containedwithin an outer ball race 83. The pin through the ball bearing and isheld in position by a strap 94 which is secured to a downwardlyextending bracket Q5. by the bolts 96. The bracket 95 may be mounted onany suitable portion of the engine. The outside periphery of the ballrace 93 is adapted to bear against the right-hand end of the cap screw54 which has the same function as was explained in connection with thesimilar element of Figure 5. It will be noted that the ball bearingstructure Q1, 92, 93, in effect, constitutes a cam so that as the pivotpoint 8'! is moved upwardly or downwardly the outer surface of themember 93 will cause the arms 56, 52, to rock on their pivot 5i. Byarranging the pin 90 eccentric with respect to the ball bearingstructure and the circular portion 88 of the arm 88, the necessity for abellcrank lever such as the structure 32, 33 of Figure 5 is eliminated.

As the intake vacuum in the manifold l is reduced, due to the impositionof a load at the generator 8, the bellows 82 will elongate downwardlyfrom the fixed point 83, swinging the arm 82; clockwise and causing therocker arrn elements 50, 52 to move in the counterclockwise directionabout their pivot 51. The butterfly valve 59 is therefore given a newsetting, causing the valve to, open further in order to admit more fuelgas to the manifold. The spring Bi serves to assist the bellows 82 toexpand against thepressure of the atmosphere changes effectively appliedto the outside surface of the bellows. The threaded rod l8 may be turnedto effect any change in adjust ment of the spring 8|, and the rod isthenlocked in position by the nut 19.

Instead of employing a bellcrank lever mounted on a ball bearing fortranslating the movement of the element 2?, as in Figure 5, to ahorizontal movement at the screw member 54, or a modified form ofball-bearing-mounted earn, as seen. in Figure 8, there may be employed asimple lever system for effecting these movements. Thus in Figure 9 thestrap 29 is provided with a pivot 91- formed by a screw, and a lever 93is adapted to swing about the pivot, one end of the lever being,connected to a rod 99 which extends downwardly from the bellows we, andthe other end of the leve may be connected through a link Hill to. apivot m2 provided on the end of the screw: 54. In this modification thebellows H3 3 may be of the type shown and described in connection withFigure 5, in which case the bellows is contained in a casing and itsexterior is subjected to the intake vacuum. On the other hand, thebellows 5% may be of the type explained in connection with Figure 8, inwhich the intake vacuum is introduced to the interior of the bellows.

From the foregoing it is evident that I have disclosed variousstructures by which the butterfly or other fuel valve is given a newsetting when the load changes, and this setting is controlled by theintake vacuum of the engine. In Figure 5 the vacuum is taken to theoutside of the Sylphon bellows, whereas in Figure 8 the vacuum is takento the interior of the bellows so that the bellows responds in theopposite manner for a given change in the vacuum, but in both cases themovement of the bellows is carried through a speed governor to effectthe proper change in the position of the valve.

It will be understood that I desire to comprehend within my inventionsuch modifications as 99 is extended come within the scope of the claimand the invention.

Having thus fully described my invention, what I claim as new and desireto secure by Letters Patent, is:

In combination, an internal combustion engine subject to variable loads,a governor, a valve in the intake of said engine, a lever connected tosaid valve and a second lever connected to and operated by saidgovernor, linkage means connecting said levers, and abellows theoperation of which is controlled by the pressure of the intake manifoldon the engine side of the valve, said bellows having opposite end platesand being mounted on and supported by said linkage means to cause saidlinkage means to be lengthened or shortened according to the engine fuelpressure, said bellows being located between said valve and saidgovernor whereby the engine speed is maintained constant notwithstandingchanges in the engine load, said linkage means consisting of a pair ofrods whose one end is connected to each lever respectively and whoseopposite end is connected to each end respectively of the said oppositeend plates of said bellows.

' EDWARD A. HOBART.

